Springbok fly-half MornÃ© Steyn could miss Sunday's Test against Scotland at Murrayfield due to a back injury.
Steyn went off in the 18th minute of Saturday's victory over Wales in Cardiff due to the pain of a back spasm.
Springbok boss Heyneke Meyer revealed that Steyn actually suffered the spasm shortly before the kick-off and played through the pain until he could no longer run.
"I was worried about him," Meyer revealed.
"Just after the warm-up his back went into spasm. We thought it would release but he couldn't run at all and we don't want to risk any injury going forward."
Meyer was hopeful Steyn would recover in time for Sunday's Test but said they would know more on the seriousness of the injury after tests on Monday.
"It's not a big injury and the fact that we brought him off quite early helped," he added.
"This is a seven-day turnaround so we have a bit more time but the great thing is we're starting to build depth now."
With a short turn around between the Murrayfield clash and South Africa's final Test against France, it is possible Steyn will be given a break.
"I am going to have to manage the players as there is only a five day turn-around," said Meyer.
"We want the players to be fresh for the French game so it is something I am going to have to assess. It is not about just giving caps away and the players that come in will be good enough to play for the Boks."
Meyer admitted losing Steyn was a blow but praised Pat Lambie, who moved to fly-half after starting at full-back, and Willie le Roux, who then took over Lambie's role at the back.
"It was a big setback early in the game," said Meyer.
"I wanted to see Pat at full-back and then he came in at 10, but I think Willie did brilliantly. He was under pressure from the previous game.
"Defensively he was great, he's worked really hard on his kicking game and contesting in the air.
"This is a total different game. This isn't Championship rugby. You can't play from scrums, you don't get any quick ball and our tactical kicking was much better so that was probably the difference on the day."